This section provides background information related to the present disclosure which is not necessarily prior art.
Virtually all motor vehicles equipped with internal combustion engines incorporate a “serpentine” drive belt system having a single endless drive belt and a series of pulleys. The pulleys derive rotary power from the endless drive belt and operate to drive various vehicle accessories such as, for example, the engine fan, the power steering pump, the water pump, the alternator and the air conditioning compressor. The endless drive belt that drives each of these accessory pulleys is, in turn, driven by an engine pulley that is connected to the crankshaft of the internal combustion engine. To reduce the transfer of vibrations and oscillations between the crankshaft and the serpentine drive belt system, the engine pulley, sometimes referred to as the “crankshaft pulley”, may include a torsional vibration damper that functions to reduce the amplitude of the angular vibrations delivered by the crankshaft.
Integrated crankshaft pulley-torsional damper units, commonly referred to as “crankshaft dampers”, may include a hub configured to be rigidly connected to the crankshaft, a driven member, and at least one ring of elastomeric material connecting the hub to the driven member. The elastomeric material functions to filter/absorb the torsional oscillations transferred to the hub from the crankshaft. In many instances, the hub includes an integral pulley and the driven member is an inertia ring. The elastomeric material is typically compressed between the pulley and the inertia ring to provide the requisite slip torque for absorbing the torsional vibration.
Automotive pulleys can be made by spinning sheet metal using a number of different processes known in the industry. However, crankshaft dampers typically must be stronger and more massive than ordinary sheet metal pulleys. Specifically, a greater mass is required to provide the requisite amount of inertia to absorb crankshaft vibration. As such, many pulleys and inertia rings associated with crankshaft dampers are made from forgings or castings. Unfortunately, the expense and time required to machine these components is prohibitive. As an alternative, some components of the crankshaft damper can be flow formed from sheet metal but can only be made up to a certain blank thickness in terms of economics and practicality.
In view of the above, there is a recognized need in the field of automotive harmonic dampers generally and crankshaft dampers specifically to manufacture components, such as inertia rings, using alternative manufacturing processes for reducing expense and providing high quality components.